A combined head-medium micromagnetic model is used to analyze servo systems for 10 Gbit/in2 recording. Servo patterns are recorded using a micromagnetic medium model to accurately describe the edge-track and noise phenomena. A micromagnetic spin-valve model is then used to replay the recorded information and obtain the position error signal (PES) as a function of off-track position. The results show that the PES linearity is a strong function of the write gap width and deep gap field